hello Rashad,for frequency

[dagakshay]

hello Rashad,

for frequency meter use counter of 8051. which is inbuilt peripherial of 8051. ADC will convert the input analog voltage to equivalent calibarated dital binary digits. so you can dispaly that voltage. here i am pasting a link hoe to use ADC. check it out.

http://www.engineersgarage.com/microcontroller/8051projects/interface-ADC0808-using-clock-AT89C51-circuit